Bernd Steffes

A first prospective randomized controlled trial to decrease bacterial load using cold atmospheric argon plasma on chronic wounds in patients

Background  Bacterial colonization of chronic wounds slows healing. Cold atmospheric plasma has been shown in vitro to kill a wide range of pathogenic bacteria.

Successful and safe use of 2 min cold atmospheric argon plasma in chronic wounds: results of a randomized controlled trial

Background  The development of antibiotic resistance by microorganisms is an increasing problem in medicine. In chronic wounds, bacterial colonization is associated with impaired healing. Cold atmospheric plasma is an innovative promising tool to deal with these problems.

Plasma applications in medicine with a special focus on dermatology

The recent tremendous progress in understanding physical plasma phenomenon, together with the development of new plasma sources has put growing focus on the application of plasmas in health care. Active plasma components, such as molecules, atoms, ions, electrons and photons, reactive species, ultraviolet radiation, optical and infrared emission and heat have the ability of activating, controlling and catalysing reactions and complex biochemical procedures. Thermal and non‐thermal (i.e. cold) plasmas – both already widely established in medicine – are used for various therapeutic applications. Particularly in dermatology, plasma applications hold big potential, for example, in wound healing, such as efficient disinfection or sterilization, therapy of various skin infections or tissue regeneration. This review gives an overview on potential plasma applications in medicine – including the recent research on skin diseases – and summarizes possible interactions between plasmas and living tissue.

Frequency dependence of microparticle charge in a radio frequency discharge with Margenau electron velocity distribution

rf discharges are widely used in complex plasma experiments. In this paper, we theoretically investigate the dependence of the particle floating potential on the discharge frequency, assuming the model Margenau expression for the electron velocity distribution function. In doing so we use the orbital motion limited cross section to calculate the electron flux to the particle and collision enhanced collection approximation for the ion flux to the particle. The floating potential is then obtained from the flux balance condition. It is shown that for typical plasma conditions in laboratory rf discharges, normalized floating potential grows with increase of the discharge frequency in collisionless regime and decreases in weakly collisional regime. However, variations in the floating potential are usually small when plasma parameters do not depend on the rf frequency.

Applications in plasma medicine: a SWOT approach

Cold atmospheric plasma (CAP) is a novel tool for various applications ranging from hygiene and cosmetics to medicine. In recent years, various CAP devices have been developed for medical applications especially for skin disinfection, blood coagulation, wound healing, and even for cancer treatment. CAPs have bactericidal, fungicidal, virucidal, and sporicidal effects due to the production of reactive species, ultra-violet radiation, electrons, ions, and so on. Therefore, CAPs have the potential for usage in hospital and personal hygiene. CAPs for medical purposes have to be designed individually, e.g. the dose and the plasma properties to eradicate bacteria from cell surfaces are different from the properties used to stop the proliferation of cancer. The CAP devices for medical purposes have to be designed in such a way, so that these are fully compatible with the international safety regulations (especially for the amount of produced reactive species, UV emission, and electrical current). However, the highest efficacy is reached by considering the combination of different CAP components (charged particles, reactive oxygen, and nitrogen species, heat, electric field, and photons), the way of application (direct or indirect with [different distances from the target cell]), the different reaction phenomena in and around the target cell (cell membrane and intracellular biochemistry) along with the defense mechanisms in and around the target cells. Our group has developed a number of different CAP devices using the microwave technology (e.g. MicroPlaSterβ and NanoPlaSter), and the surface micro discharge technology (e.g. HandPlaSter, FlatPlaSter, CylindricalPlaSter, PersonalPlaSter, MiniFlatPlaSter). The strength, weakness, opportunity, and threat analysis show that the technique to use CAP for medical purposes is affordable, simple, easy to handle, and case sensitive – although more studies on the mechanism of the interaction of CAP and cells are necessary. However, the usage of CAPs in ‘medicine – ‘plasma medicine’ – shows a newfangled hope for the development of molecular medicine in the near future possessing an immense market potentiality.

PPPS-2013: This is a sample abstract submission: Cold atmospheric argon plasma accelerates wound healing in chronic infected wounds in patients

Objectives: Chronic infected wounds are both socioeconomic and medical problem. Combating bacterial resistance is on of the greatest challenges in the 21st century. In previous reports, 2 min and 5 min cold argon plasma treatments led to a significant reduction in bacterial load in chronic wounds of various causes in patients, regardless of the bacterial species. The observed bactericidal effect of plasma therapy relies on the synergy of reactive oxygen and nitrogen species, charged particles, electric fields, and UVR. This study evaluates the effect of CAPs on wound healing in vivo. Methods: Hard-to-heal chronic wounds of various types in 70 patients (Group A) were treated with cold argon atmospheric plasma for 3-7 minutes. The wound size before and after a course of treatment was compared for plasma-treated and control wounds. Subgroup analyses were performed for all chronic venous ulcers (n=29, Group B) and 5 min plasma treatment of chronic venous ulcers (n=18, Group C). Results: Retrospective analysis of Group A revealed a 10.4 % reduction in width of plasma treated wounds compared to 4.2 % in the control (p=0.270). Length reduced by 8.2 % compared to 5.1% respectively (p=0.068). In Group B a significantly greater reduction in width (17.9 %, p=0.03) was measured in plasma-treated ulcers compared to controls (0 %). However changes in length were not significantly different (9.1 % vs. 8.9 %, p=0.46). The Group C sub analysis showed a highly significant reduction in width (14.6 % vs. 0 %, p=0.008) with plasma treatment but not in ulcer length (2.7 % vs. 8.4 %, p=0.352). Conclusions: This study demonstrates for the first time that plasma treatment can actually accelerate wound healing in a range of chronic wounds, but particularly chronic venous ulcers.

The charging of dust particles in the range of very high discharge frequencies

Capacitively coupled plasmas are widely used in a variety of thin film etching and deposition applications. The studies and experimental investigations in this field have shown that increasing frequencies above the conventional 13.56 MHz results in the increase of the deposition rate and at the same time minimizes the film damage [1]. On the other hand dust particles are often present in the plasma reactors as a sputtering or nucleation product and may influence the manufacturing. Therefore, controlling the behavior of dust particles is essential for improving of the manufacturing techniques in the low temperature plasma processing.

Argon plasma vs. air plasma: Characteriazation and interaction with biological systems

Recently, there has been enormous progress in plasma medicine. New groups have joined this area of research. New plasma devices have been developed and tested for biomedical applications. The difference in plasma production methods and composition of input gases does not allow to directly compare plasmas produced by various devices and predict their effect on biological systems.